Temperature indicating and temperature controlled and controlling device



Aug. 19, 1941 s BROWN ETAL 2,253,263 TEMPERATURE INDICATING AND TMLERATURE CONTROLLED AND CONTROLLING DEVICE Filed Dec. 20, 1939 2Sheets-Sheet l Aug. 19, 1941. s BROWN 2,253,263 TEMPERATURE INDICATINGAND TEMPERATURE CONTROLLEDAND CONTROLLING DEVICE Filed'Deo. 20, 1939 2Sheets-Sheet 2 Panelists-i9. i 41 ,2,253:263

umrso sures PATENT OFFICE j 1 2.253.283C- Stewart 1:. Brown, Alexandria,va. and Welllng- 1 tonB. Sullivan, Silver Spring, Application Decemberso, 1939, Serial no. mass i "reclai (cine-101) The object of thisinvention is to provide a or controlled, and the heat transmittingcapacvery simple and inexpensive device, of a nature ity of the mass issuch as to transmit the heat to be easily and quickly, applied tosurfaces of necessary'to cause control elements, such as mechanismswhich are subject to. variations of fusible bodies, bimetallic strips,or the like, to

. temperature under their conditions of use. the function as hereinafterdescribed. said device serving to indicate when such surface Further,the thermal capacity of the mass is Y .ature is prevented.

has reached ajpredetermined temperature. In preferably such as tointroduce a reasonable some of the forms illustrated, the device alsotime lagin the functioning of the device, since serves to control themechanism to which it, is many of the mechanisms to which the devicewill applied, to the end that further rise of temperbe applied forprotective purposes may besubv .iected, without injury through limitedperiods. This invention also serves to indicate whether to temperatureswhich, ifcontinued through long the surface to which it is applied hasreached periods of time, would cause serious damage to Fig. l:

an undesirable temperature since' the last insuch mechanisms. spectionof the device, even thoughsuch un-. 18 Referring now to F188- 1 to 4. 5d i n tes adesirable temperature may not be existing at metallic mass.of s ch s e and co position that the moment ofa succeeding inspection.Imporit may e ca t Serve as t e m n rtant novel characteristics andcapabilities of the mal and magnetic mass above referred to. -We deviceof this invention will be set.forth in the preferably employ an alloy ofa uminum. nickel detailed description which follows. 80 and cobalt,known to the trade as Alnl but In the accompanying drawlnxs. in whichlike we contemplate the use of any material which reference charactersdesignate corresponding will have the same general characteristics anparts throughout the several views: 7 capabilities as Alnico.

Figure 1 is a central vertical sectional view of Such a meta- 1s cap bleo be pe ma n y a structure illustrating. one embodiment of the IImagnetized, n wh n a netized will have sufllinvention: l cient magneticstrength to support not only its Fig. 2 is a front elevation of thestructure of i wn "w fl h Weight of t associ ted r parts, and thus serveto hold the whole struc- Fig. 3 is a plan view illustrating the deviceture securely upon a metallic surface that is to applied to a partsubject to changes of temperso be pro ected- 37 fproteo edfl we meanthat ature, as hereinafter described;- the device of the invention willindicate exces- Fig. 4 is a face view of the device of Fig. 1, sivetemperature rise in the part protected, or illustrating the signal discin-its dropped or inthat it will function to bring about a stoppagedicatlng position; of suchmechanism until the conditions respon- Fig. 5is a vertical sectional view of a modified sible for such excessivetemperature, rise have form of the invention; been corrected. Fig. 6 isan enlarged fragmentary sectional A steel insert 8 receives a brasssleeve 1 and view through the ratchet wheel and associated a brass D 118A brass tor or shaft 9 is $01- parts of Fig. 5; dered within the sleeve1, this solder constituting- Fig. 7 is a vertical sectional view of afurther a fusible link between the stationary brass sleeve modification;and the rotor or shaft' 9. A ratchet wheel in is Fig. 8 is a frontelevation of the structure of fixed upon the shaft 8. A half disc II ismounted Fig. 7; to turn upon the outer end of the shaft 9 and is Fig. 9is a vertical sectional view of a further held in pl y n t L A p i 3 hasits outer modification; end fixed to a. pin ll which projects rearwardlyFig. 10 is a sectional view on line I 0-! of from the face of the halfdisc II, the inner end Fig. ,9 withthe casing in elevation, and 'of thisspring being fixed at It to the steel in- Fig. 11 is a diagrammatic viewillustrating sert 8. A pawl i6 is carried by the half disc, some of theuses served by the-device. and the end of this pawl engages the teeth ofBroadly stated, the invention, in all of its 60 the ratchet wheel". 1embodiments, contemplates the use of a mass Thus the spring normallytendsto swing the constituting both a thermal and amagnetic elehalf discin the direction of the arrow A in Fig.

ment. The magnet is a permanent one, of such 2 but isrestrained fromdoing so byithe fact that strength as to hold the device upon metalsurthe end of the pawl I8 is engaged with a ratchet faces, thetemperature of which is to be indicated wheel which is immovable untilthe fusible link.

2 constituted by the solder, melts. when this solder melts, the ratchetwheel is free, and the half disc, pawl and ratchet wheel all turn bodilytogether in the direction of the arrow A until the disc is brought tosubstantially inverted position or until it lies below instead of abovethe shaft 9.

The structure described is contained within a casing H, the upper halfof the front of .which is closed as indicated at l8, and the lower halfof which, is open, as indicated at 19. When the disc is brought to itslower or indicating position,

it is visible through the open lower half of the casing, and thus servesto indicate to an observer that the mechanism has been actuated by theexistence of enough heat to melt the solder.

The outer face of the disc is preferably distinctively colored, red, forexample, and thus a mere glance at this signaling device will showanobserver whether the signal has been actuated.

Fig. 4 shows the appearance of the signal after the inner face of thecover, the tall 24 of which bears against the mass 5 and tends to throwthe cover 2| outwardly and downwardly.

This tendency of spring 24 to throw the cover outwardly is resisted by apawl 25, which is constituted by an inwardly turned end of the strip 23.This pawl engages the teeth of a ratchet wheel 23, said ratchet wheelbeing fixed upon a shaft 21 and said shaft in turn being held againstturning by being soldered to a preferably brass sleeve 28 (Fig. 6), saidsleeve in turn being carried by the mass 5.

The solder is indicated at 29 and constitutes a fusible link. When thissolder melts under the influence of excess heat, the ratchet wheel isfree to turn and the spring actsto throw the cover open. The fact thatthe cover is open warns the inspector that the surface B has been, atsome time since the lastinspection, subjected to a temperature beyondthe range intended.

to illustrate a very simple form of the invention, in which the mag-Figs. '7 and 8 are intended netic thermal mass 5 carries a sleeve 30,within which a shaft 3| is soldered as indicated at 32. The outer end ofthis shaft carries a flag 33,

,and in the initial setting of the device, this flag may be tippedslightly beyond the vertical in one direction or the other to cause itto tend to fall, as for example, in the direction indicated by the arrowC in Fig. 8, when the solder or other fusible material 32 melts.

In Figs. 9 and 10, we have indicated a structure employing a bimetallicstrip as the heat affected element in lieu, of the fusible material.This structure is very similar to that illustrated in Fig. 1 andcomprises a thermal magnetic mass 5', sleeve 34, central shaft 35, halfdisc 36 and spring 31, all functioning like the corresponding parts inFig. 1. However, in lieu of the ratchet wheel, a cam 38 is provided onshaft 35, said cam having a shoulder 39. The action of the spring tendsto move this shoulder against the end of a bimetallic strip 40.

This strip 40 is carried by a shank ll, of con-.

contemplates the use of siderable mass, and which shank passes throughand thus is in heat exchange relationto the mass 5'. Upon heating of themass beyond a predetermined degree, the bimetallic strip 40 flexesupwardly enough to free its free end from the shoulder 33, whereupon thespring acts to throw the half disc downwardly to indicating position, itbeing understood that this structure a cover 42, like the correspondingelement of Fig. 1.

If desired, an adjusting screw 40 may be employed to effect what is, insubstance, a stiffening of the bimetallic strip to thus vary thetemperature atwhich the device will function. Adlusting screws of thisnature are common in conjunction with thermally actuated bimetallicstrips, in many relations. By "thermal mass as used in the accompanyingspecification and claims, we mean a mass composed of a metal and insumcient size to take up and transmit to a thermally actuated element(fusible link or bimetallic strip) the necessary degree of heat to causethe latter to function. This thermal mass should also be of. .suchcapacity as to introduce a reasonable time lag, as hereinbefore setforth.

The diagrammatic Fig. 11 is intended to indicate that this devicemay-serve'to do more than give a merely visual indication. The halfdisc,

or any other moving part of the structure, may,

when released and actuated, control an electric circuit. In Fig. 11, thehalf disc II has been shown as having moved a contact strip 43 toward acontact strip 46 to thus close a circuit at 45 and energize the circuit56. The closing of this circuit may be caused to sound an alarm, as

through-the medium of a bell 41, or it may be utilized to energize themagnet 48 of a relay. The armature 49 of this relay may be utilized toopen or close another circuit. For example, the

conductors 50 may constitute parts of the ignition circuit of aninternal combustion engine, to the water jacket of which the magneticmass of the signal was caused to magnetically adhere. In such a case,any failure of the flow of cooling water through the water jacket of theengine would automatically.interrupt the ignition circuit and bring theengine to a stop.

While this description has treated primarily of the use of the device toindicate abnormal rises of temperature, it is clear that it could alsobe used to indicate the existance of abnormally low temperatures bymerely changing the nature of the bimetallic element. Ml. That is tosay, if this bimetallic element were such as to cause its free end toflex upwardly upon decrease of temperature rather than upon increase oftemperature, then the signal would function when such abnormally lowtemperature was reached.

One of the important uses of the device of the present invention is inconnection with electric transformers such as are used by electric lightand power companies. Most of these transformers contain a body of oil,and it is the present practice to have men test the temperature of theoil in the transformer from time to time to determine whether a giventransformer is being overloaded. This requires that the men doing thiswork climb to positions of considerable elevation to reach thetransformers, since the latter areusually upon elevated structures. Bythe use of the device of the present invention, the condition of thetransformer may be determined by a mere visual inspection from theground, and thus the in uries which have sometimes been caused by menbeing burned or falling, may be avoided.

arcane:

As is illustrated in Fig. 3, a a only necessary to place an indicator,such as we have described, against the casing B of an overhead,oil-containing transformer to render it possible for an in-.

spector to easily and quickly determine, visually, and from the ground,whether such transformer has been overloaded and consequentlyoverheated. It is not necessary to tap any screw holes in the casing ofthe transformer in order to secure this result, since the device willadhere magnetically to the metallic casing of the transformer and willsupport its own weight as well as the weight of the signal partsassociated therewith.

We are aware of the fact that it has heretofore been proposed to holdvarious kinds of objects in place upon magnetic surfaces through themedium of electromagnets. The use of such devices as these presuppose acondition where electric current is available. In many, even in most, ofthe places where our device will be found of the greatest utility,electric current is either not readily available or else the cost ofmaking connection with it would be prohibitive.

Our invention contemplates the use of a per manent, self-containedmagnet, but a magnet of a kind not commonly contemplated for use in sucha relation as is herein described. Ordinary steel, which, in years past,has commonly been employed in attempts to make simple permanent magnets,would be wholly unsuitable for use in connection with the manufacture oithe device of our invention, for the reason that magnets made or .theseformerly employed materials would not possess the strength to supportthe weight of a mass adapted to yield the heat exchange andtimelagqualities necessary to the production of a satisfactory articleof this sort.

It is to be understood that the several examples shown in theaccompanying drawings are illustrative merely of the principles of theinvention. Many ways will readily suggest themselves, to those skilledin the art, for the accomplishment of the desired result. Therefore, itis to be understood that the invention is not limited to the preciseconstructions set forth, but that it includes within its purviewwhatever changes fairly come within either the terms or the spirit ofthe appended claims. 7

Having described our invention, what we claim is:

1. In combination, signaling means controlled by temperature changesbeyond a pre-determined degree, and a heat transmitting, metallic masspermanently magnetized and with respect to which mass said signalingmeans is mounted in heat exchange relation and through which 5 to becapable 'of supporting its own weight and I mass heat is transmittedfor. the control of the signaling means.

. mass, and means tending to move the indicator i from one position toanother, said detent being of anature to be affected by heat transmittedthereto thru said mass to thereby control the indicator undertemperature changes.

3. In a device of the character described, the

combination with a permanently magnetized ,heat storing and transmittingmass, of an indiester 1 comprising a swinging signal. a detent whichnormally prevents said signal from swingreaches a pre-determinedtemperature, to thereby permit the signal to swing.

4. In a device or the character described, the combination with apermanently magnetized heat storing and transmitting mass, of anindicator comprising a movable part, a spring tending to move the partin one direction, a member normally held against movement with relationto the mass, thermally controlled means, operable when said mass reachesa pre-determined degree, to release the normally held member, andinterengaging means between the movable part and the fixed member. l

5. A structure as recited in claim'4 wherein the thermally controlledmeans comprises a body of fusible material.

6. A device of the character described, comprising a thermal andpermanently magnetized ing the signal against movement until saidfusible material is melted.

'1. A device of the character described comprising a thermal mass,permanently magnetized,

a shaft secured thereto by a body of fusible material, a ratchetfixedup'on said shaft, a signal disc mounted to turn with respect tosaid shaft. a pawl carried by the signal disc engaging the ratchet, anda-spring tending to move the disc, said disc being held by theengagement oi the pawl with the ratchet until the bodyof fusiblematerial melts.

8. A structure as recited in claim 7, in combination with a casinghaving' a closed upper portion and an open lower portion, the saidsignal being visible through the open lower portion after it has beenreleased and moved.

9. A device of the character described, comprising a thermal mass,permanently magnetized to a strength necessary to support its own weightand the weight of the parts carried thereby, a

shaft passing through said mass, 9. body of fusi his material holdingthe shaft against turning with respect .to the mass, and a gravitallyactuated flag upon the shaft, disposed in position to fall to indicatingposition whenever the shaft is released by the melting of the fusiblematerial.

10. The combination with a body of metal, of a nature to constitute athermal and permanently magnetized mass, magnetized to such strength asthe weightof the parts carried thereby, of a movable signal, meanstending to move said signal in onedirection and restraining meansrestraining said signal against movement, said restraining meanscomprising a bimetallic strip supported in heat exchange relation tosaid mass and engaging ashoulder portion carried by the si nal 11. Thecombination with a body of metal, of a nature to constitute a thermaland permanently magnetized mass. magnetized to such strength as to becapable of supporting its own weight and the weight of the parts carriedthereby, of a movable signal, a shaft upon which the signal is mounted,a spring tending to move' said signal in one direction, a cam upon theshaft having a shoulder, a bimetallic strip, the end of which engagessaid shouldcr, and a heat transmitting ing, said detent being in heat exhange relation member car ying th m fll i p; said memher lying inintimate and heat exchange relation to said mass. 7

12. A device of the character described comprising a mass of metal,permanently magnetized to a strength to support itself and the partscarried thereby, an indicating member, and means causing said member totend to move from one position to another position, thermally controlled,means normally restraining said member and lying in heat exchangerelation to said mass, said mass of magnetized metal serving to supportthe whole upon a metallic object, the temperature of which is to beindicated, and the heat from which is transmitted through said mass tothe thermally controlled restraining means.

13. A signal of the character indicated,-comprising an indicatorarranged to tend to move from one position to another, means restrainingsaid indicator of a nature to be responsive to a predetermined degree oftemperature change, a

tallic surface, and

which the indimagnetic metallic mass upon carried, and

cator and restraining means are with which mass the restraining means isin heat exchange relation to therebybe released upon a rise oftemperature within said mass of a determined degree, the said mass beingof such volume and nature as to be magnetizable to a strength sufiicientto supportthe whole in conrestraining means when maintained for only amaterially shorter period of time.

STEWART K. BROWN. WELLINGTON B. SULLIVAN.

